1. Field of the Invention
The present invention relates to a tire vulcanizer. More particularly, the present invention relates to a tire vulcanizer in which a distance between top and bottom mold mounting members can be adjusted based on a height of a mold.
2. Description of the Related Art
A tire vulcanizer is a machine in which an unvulcanized raw tire (a green tire) received in a mold is vulcanized and patterned by applying heat from both inside and outside the mold. In general, a mold of the tire vulcanizer comprises a two-part mold which is divided into two, top and bottom, parts. A top mold and a bottom mold of the two-part mold are respectively retained by a top mold mounting member and a bottom mold mounting member. Then, opening and closing of the mold can be achieved by moving up and down the top mold mounting member along a vertical direction relative to the bottom mold mounting member.
Here, when the mold is replaced in order to vulcanize a different type/size of the raw tire in the tire vulcanizer, the height (thickness) of the mold may be changed. As a result of such a change in height of the mold, it becomes necessary to adjust the distance between the top and bottom mold mounting members, or other features based on the height of the mold. For this reason, various adjustment methods have been conventionally suggested.
For example, a tire vulcanizer described in JP Kokoku (Examined Patent Publication) No. H01-45403 has a top die (the top mold) installed on a top link side. Then, after the top die and a bottom die (the bottom mold) are brought into a closed condition by moving down the top link, a clamping force is applied via the top link between the top die and the bottom die by a crank mechanism. A die height adjusting threaded shaft and a die height adjusting threaded sleeve into which the adjusting threaded shaft is movably screwed are inserted between the top link and the top die, and an amount of screwing the adjusting threaded shaft into the adjusting threaded sleeve is changed according to a height of a die (the mold), to thereby adjust a distance between a top platen (the top mold mounting member) and a bottom platen (the bottom mold mounting member).
On the other hand, in a tire vulcanizer described in JP Kokoku (Examined Patent Publication) No. H03-70610, an upper die (the top mold) and a lower die (the bottom mold) are squeezed via a lifting table by a pressure cylinder. An extendable spacer is inserted between the lifting table and the pressure cylinder to transfer a squeezing force from the pressure cylinder to the upper die. Then, a threaded part formed on a top of the spacer is mated in a nut which is contacted with the pressure cylinder, thereby allowing a length of the spacer to be adjusted by rotating the nut. The length of the spacer is adjusted based on the height of the die (the mold).
Meanwhile, in a tire vulcanizer described in JP Kokoku (Examined Patent Publication) No. H01-24048, a top die (the top mold) and a bottom die (the bottom mold) can be opened or closed by lifting up and down an upper slide using a mechanical lifting means. A mold height adjusting device is installed between a top link and the top die, and a distance between an upper platen (the top mold mounting member) and a lower platen (the bottom mold mounting member) is adjusted in accordance with the height of a mold by the mold height adjusting device.
In any of the tire vulcanizers described in the above patent publications, however, the adjustment based on the height of the mold is conducted through the use of the mold height adjusting device, etc. installed at a location vertically extended from the mold as described above, which presents a problem in that an overall height of the tire vulcanizer is increased. There is another problem as described below. The adjustment based on the height of the mold is performed depending on the amount of screwing the adjusting threaded shaft into the adjusting threaded sleeve, an amount of rotation of the nut relative to the threaded part of the spacer, etc. as explained above, which make the adjustment difficult to achieve.